In simple sense, if trader don't want to go into much of the complications of GST (Just as regular dealer) he can opt for composition scheme, if it's within the limit of turnover, but it also comes with limitation, like no inter state sale, can't sale through e-commerce operators like amazon, flipkart etc. but lower tax rates, and suitable for small taxpayers...Govt provides credit in GST but it comes with lods of compliance in form of return filing (Now under QRMP it's less but based on turnover), it depends on cost benefit analysis and market factors...(If traders, buyer is regd dealer then there is a less chances to go for composition because he will not get any input credit ).